System and method for controlling the temperature in a structure

ABSTRACT

There is described a system for controlling the temperature in a structure that has exterior walls. At least a portion of at least one exterior wall comprises a cement core having a layer of insulation on an interior face and an exterior face of the cement core, and at least one fluid conduit embedded in the cement core. A source of temperature-controlled fluid is connected to the at least one fluid conduit.

FIELD

This relates to a system and a method for controlling the temperature ina structure.

BACKGROUND

The most common method of controlling the temperature in a structure isto insulate the building and provide a heat or cooling source inside theinsulative envelope. One example of this type of structure used forcooling can be found in U.S. Pat. No. 6,810,945 (Bissevain) entitled“Conditioning the air in a structure utilizing a gravel heat exchangerunderneath the slab.” Another method of controlling the temperature in astructure is to provide an air envelope in the walls of a building, suchas is described in U.S. Pat. No. 6,293,120 (Hashimoto) entitled“Building air conditioning system using geothermal energy.” Otherexamples include U.S. Patent Application Publication No. 2010/0198414(Kroll et al.) entitled “Systems and methods for controlling interiorclimates,” which describes a structural wall panel that includes anembedded fluid conduit, where the circulated fluid temperature is higherthan the desired room temperature in order to heat the room, and U.S.Pat. No. 4,250,957, which describes pumping water from an undergroundreservoir into wall panels.

SUMMARY

There is provided a system for controlling the temperature in astructure. The structure has exterior walls. At least a portion of atleast one exterior wall comprises a cement core having a layer ofinsulation on an interior face and an exterior face of the cement core,and at least one fluid conduit embedded in the cement core. A source oftemperature-controlled fluid is connected to the at least one fluidconduit.

According to another aspect, there may be more than one fluid conduit inthe at least one exterior wall. The source of temperature-controlledfluid may circulate temperature-controlled fluid separately through eachfluid conduit.

According to another aspect, the source of temperature-controlled fluidmay comprise a ground-source energy source, a solar energy source, acombustion energy source, and/or a refrigeration source. The source oftemperature-controlled fluid may be maintained at a temperature between10 and 15 degrees Celsius, and preferably between 10 and 20 degreesCelsius. The R-value of the layers of insulation may be between 10 and20, and may be as low as 6 or 7 and may be higher than 20.

According to an aspect, there is provided a method of controlling thetemperature in a structure. The method comprises the steps of: embeddinga fluid conduit in a cement core of at least one exterior wall, the atleast one exterior wall comprising insulation on an interior face and anexterior face of the cement core; and circulating temperature-controlledfluid through the fluid conduit to maintain the cement core within apredetermined temperature range.

According to another aspect, there may be more than one fluid conduitembedded in the cement core, and temperature-controlled fluid may becirculated separately through each fluid conduit. A controller maycontrol the temperature in each fluid conduit.

According to another aspect, one or more fluid conduits may transferheat into a source of temperature-controlled fluid, and one or morefluid conduits may transfer heat out of the source oftemperature-controlled fluid.

According to another aspect, the temperature-controlled fluid may becirculated through at least one of a ground-source energy source, asolar energy source, a combustion energy source and a refrigerationsource.

According to another aspect, the interior of the structure may beheated, such as by a heater, to a target temperature, and thetemperature-controlled fluid may be at a temperature that is less thanthe target temperature.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features will become more apparent from the followingdescription in which reference is made to the appended drawings, thedrawings are for the purpose of illustration only and are not intendedto be in any way limiting, wherein:

FIG. 1 is a side elevation view in section of an insulated cement wallwith thermal loop.

FIG. 2 is a schematic view of an insulated cement wall connected to aground loop.

FIG. 3 is a schematic view of an insulated cement wall with abuffer/storage loop, ground loop, solar collector loop and an auxiliaryheating loop.

FIG. 4 is a side elevation view in section of a structure using thesystem.

FIG. 5 is a chart showing the ambient air temperature compared to theground temperature at various depths in Slave Lake, Alberta.

FIG. 6 is a chart comparing the ambient air temperature to the groundtemperature at a depth of 300 cm at in Slave Lake, Alberta.

DETAILED DESCRIPTION

A system for controlling the temperature in a structure, generallyidentified by reference numeral 10, will now be described with referenceto FIGS. 1 through 6.

The discussion below assumes that all the entire exterior walls 100 of astructure 102 (shown in FIG. 4) are made using the teachings describedherein. In most circumstances, this will provide the best results.However, it will be understood that the teachings discussed herein mayalso be applied to structures where only some of the exterior walls, ora portion of the walls, incorporate the teachings below, depending onthe preferences of the user and demands of the situation.

FIG. 1 shows a cross section of a wall 100 having a cement core 17sandwiched between an inner insulating layer 11 and an outer insulatinglayer 12. It will be understood that the term “cement” is intended to beinclusive of different types of cement that may be used for structuresknown to those skilled in the art, and includes concrete and othercement composites. The inner and outer insulating layers 11 and 12preferably have an R-value of between 10 and 20, but may be as low as 6or 7, and may be higher, depending on the preferences of the user andthe available resources. A fluid-carrying thermal loop 20, or fluidconduit, is embedded in the inner wall cement 17.

The thermal loss across the inner insulating layer is dependent on thetemperature difference (ΔT) between the interior wall finish 13, such asa sheet of drywall, and the inner wall cement 17. Likewise, the thermalloss across the outer insulating layer is dependent on the ΔT betweenthe cement 17 in wall 100 and the outside wall finish 14, such assiding, stucco, etc. Controlling the temperature of the cement in wall100 therefore allows control of the heat loss and gain of the buildinginterior.

FIG. 2 shows a primary thermal loop 20 which moves fluid through theinner wall cement 17 by using a variable speed circulating pump 21. Asdepicted, a microprocessor pump controller 25 monitors the temperatureof the circulating fluid via a temperature transmitter 22. Without anyheating or cooling systems attached to the primary loop, the temperatureof the circulating fluid would be equal to the inner wall temperature.The inner wall temperature would vary depending on changes in outsideand inside temperatures due to the thermal energy transfer across theinsulating layers. The pump controller 25 can calculate the thermalenergy gain or loss across both insulating layers based on readings fromthe exterior temperature transmitter 23 which is embedded in the outsidewall finish 14, and the interior temperature transmitter 24 which isembedded in the interior wall finish 13. In a preferred embodiment, athermal ground loop 26 buried underground allows the controller 25 totransfer thermal energy to and from an area that is generally warmerthan the ambient temperature in the winter, and cooler than the ambienttemperature in summer. For example, when ground loop 26 is buried about10 ft underground, the temperature will be close to a constantyear-round that is close to the annual average above-ground temperaturefor a particular geographical area. In some geographic areas, thetemperature may be maintained at a temperature of 10-15 degrees Celsius,and more preferably closer to 20 degrees Celsius when supplemented withother energy sources. Should the inner-wall temperature fall below theground loop temperature, the microprocessor will increase the speed ofthe ground loop variable speed pump 21 in order to raise the temperatureof the primary loop 20. If the ground loop 26 is sized properly, theinner wall temperature will be maintained at or close to the temperatureof the ground loop 26 even during the coldest times of the year.

When the pump controller 25 senses that the exterior wall temperature 23rises above the primary loop temperature 22, the circulating pump 21will stop, allowing thermal energy to be absorbed through the outerinsulating layer 12 into the inner cement wall. The pump 21 may startperiodically in order to sense the rise in the inner-wall temperature.Should the inner-wall temperature rise above the temperature setpoint ofthe inside, the circulating pump will start and maintain the inner-walltemperature at setpoint. Thermal energy will then be moved into theground loop. As depicted, temperature sensor 22 is used to detect thetemperature of the fluid as it exits primary thermal loop 20. In otherembodiments, there may be other sensors included or used instead, suchas sensors that sense the temperature of the wall and communicate thisinformation to the pump controller. Furthermore, there may be additionaltemperature sensors positioned inside or outside the structure thatdetect changes in the temperature to allow pump controller 25 toanticipate temperature changes.

Referring to FIG. 3, in another embodiment, the system may also includea solar collector loop 29 that the pump controller 25 can use to addthermal energy to the primary loop 20. If the solar loop 29 is ofsufficiently high temperature, it may also be used to directly heatinterior space as shown in FIG. 3, by using radiant heating lines 16.There may also be included a thermal storage loop 35, a storage looptemperature transmitter 37 and a storage loop variable speed circulatingpump 36. This can be used to create a buffer which will allow the pumpcontroller 25 to better regulate inner wall temperature due to theincreased thermal mass in the storage loop 35. The difference betweenthe primary loop temperature transmitter 22 and the storage looptemperature transmitter 37 allows the controller to calculate if thestorage loop sinks or sources thermal energy. By adjusting the speed ofthe storage loop pump 36, the controller 25 can add or remove thermalenergy from the primary loop 20 as required to control the inner-walltemperature. Finally, a conventional heating or cooling loop could beused to raise or lower the inner wall and storage loop temperatures. Forexample, a batch process may be used that is run manually orautomatically as required, such as a wood gasification burner thatdelivers a large amount of energy quickly for storage in the structureand thermal storage loop. Other types of conventional heating systemsmay also be used, such as a gas furnace, water boiler, etc. to heat. Itwill be understood that some or all of the loops may be closed systems,and that the heat transfer between loops or between loops and fluidstorage tanks may occur using heat exchangers. The fluid may be anysuitable heat-transfer fluid as will be recognized in the industry, suchas glycol, water, etc. Preferably, the fluid is selected such that itwill not freeze the lines should circulation cease for a certain periodof time.

In addition to maintaining the inner-wall temperature, the building 102may be heated or cooled using known heating or cooling systems. This maybe particularly useful in geographic areas with extreme temperatures.

Referring to FIG. 4, additional thermal loops can be included based ongeographical direction or individual room temperature requirements. Forexample, a portion of the structure 102 that receives more solar energy,such as a south-facing wall, may be on a separate loop than a portionthat receives less solar energy. In addition, the temperature in thewalls around a cold room may be kept at a lower temperature than therest of the structure. Other separate loops may include the ceiling andbasement floor. This allows the structure to be completely enclosed bytemperature-controlled thermal mass. The ability of the system to absorbsolar energy and not transfer it to the inside of the building, butrather store it for future use allows the south-facing exterior walls tobe painted black in order to maximize solar energy absorption. A layerof glazing 18 would improve solar gain even more, for example, the roofcould potentially be completely glass covered as depicted in FIG. 4. Thesolar energy collected by the solar loop can be used to directly heatthe building interior using traditional radiant heating loops. Theoverall energy requirement to heat the interior space is dramaticallyreduced, so solar heating would be feasible even in northern climates.The majority of thermal energy loss of the building exterior during thecoldest times of the year will be made up of free ground loop energy,which also is stored solar energy.

The pump controller 25 is used to control energy absorption and lossacross either one of insulating layers 11 and 12 by controlling thetemperature of the inner cement core 17. The building structure is usedto actively store thermal energy from different sources and additionalstorage loops can be added as required.

There will now be discussed the effect of the present invention incolder climates. Referring to FIG. 5, there is shown the above and belowground average daily temperatures in Slave Lake, Alberta. The trendsshown in FIG. 6 show that half of the year the ground temperature at 300cm is higher than the ambient average air. As can be seen, the ΔT acrossthe wall in January is about 2° C. based on average ambient airtemperatures. However, it is not uncommon to experience temperatures of−50° C. or lower when considering wind chill. During those days, the ΔTacross the wall would be 55° C. If, however, the inner wall temperatureis maintained at 5° C., then the heating requirement of the interiorspace is significantly reduced and constant, regardless of outsidetemperature. An inner wall temperature of 5° C. will only be effectiveif there is insulation on both the inside and outside of the wall, as itis not “high grade” heat. In the most basic form as shown in FIG. 2, thesystem can be used to reduce heating requirements during the coldesttimes of the year dramatically. Once solar heating, storage, and othersystems are added, inner-wall temperatures may be increased to 20° C.,such that interior space heating requirements may be reduced further oreven eliminated.

In this patent document, the word “comprising” is used in itsnon-limiting sense to mean that items following the word are included,but items not specifically mentioned are not excluded. A reference to anelement by the indefinite article “a” does not exclude the possibilitythat more than one of the element is present, unless the context clearlyrequires that there be one and only one of the elements.

The following claims are to be understood to include what isspecifically illustrated and described above, what is conceptuallyequivalent, and what can be obviously substituted. The scope of theclaims should not be limited by the preferred embodiments set forth inthe examples, but should be given the broadest interpretation consistentwith the description as a whole.

1. A system for controlling the temperature in a structure, comprising:a structure comprising exterior walls; at least a portion of at leastone exterior wall comprising a cement core having a layer of insulationon an interior face and an exterior face of the cement core, and atleast one fluid conduit embedded in the cement core; and a source oftemperature-controlled fluid connected to the at least one fluidconduit.
 2. The system of claim 1, comprising more than one fluidconduit in the at least one exterior wall.
 3. The system of claim 2,wherein the source of temperature-controlled fluid circulatestemperature-controlled fluid separately through each fluid conduit. 4.The system of claim 1, wherein the source of temperature-controlledfluid comprises a ground-source energy source.
 5. The system of claim 1,wherein the source of temperature-controlled fluid comprises a solarenergy source.
 6. The system of claim 1, wherein the source oftemperature-controlled fluid comprises a combustion energy source. 7.The system of claim 1, wherein the source of temperature-controlledfluid comprises a refrigeration source.
 8. The system of claim 1,wherein the source of temperature-controlled fluid is maintained at atemperature between 10 and 20 degrees Celsius.
 9. The system of claim 1,comprising a heater for heating an interior of the structure to a targettemperature, the temperature-controlled fluid being at a temperaturethat is less than the target temperature.
 10. A method of controllingthe temperature in a structure, comprising the steps of: embedding afluid conduit in a cement core of at least one exterior wall, the atleast one exterior wall comprising insulation on an interior face and anexterior face of the cement core; and circulating temperature-controlledfluid through the fluid conduit to maintain the cement core within apredetermined temperature range.
 11. The method of claim 10, whereinmore than one fluid conduit is embedded in the cement core.
 12. Themethod of claim 10, wherein circulating temperature-controlled fluidcomprises circulating temperature-controlled fluid separately througheach fluid conduit.
 13. The method of claim 12, wherein a controllercontrols the temperature in each fluid conduit.
 14. The method of claim10, wherein at least one fluid conduit transfers heat into a source oftemperature-controlled fluid, and at least one fluid conduit transfersheat out of the source of temperature-controlled fluid.
 15. The methodof claim 10, wherein the temperature-controlled fluid is circulatedthrough at least one of a ground-source energy source, a solar energysource, a combustion energy source and a refrigeration source.
 16. Themethod of claim 10, further comprising the step of heating an interiorof the structure to a target temperature, and wherein thetemperature-controlled fluid is at a temperature that is less than thetarget temperature.